<?xml version='1.0' encoding='UTF-8'?>

   <xs:schema
       xmlns:xs='http://www.w3.org/2001/XMLSchema'
       targetNamespace='urn:ietf:params:xml:ns:xmpp-sasl'
       xmlns='urn:ietf:params:xml:ns:xmpp-sasl'
       elementFormDefault='qualified'>

     <xs:element name='mechanisms'>
       <xs:complexType>
         <xs:sequence>
           <xs:element name='mechanism'
                       minOccurs='1'
                       maxOccurs='unbounded'
                       type='xs:NMTOKEN'/>
           <xs:any namespace='##other'
                   minOccurs='0'
                   maxOccurs='unbounded'
                   processContents='lax'/>
         </xs:sequence>
       </xs:complexType>
     </xs:element>

     <xs:element name='abort' type='empty'/>

     <xs:element name='auth'>
       <xs:complexType>
         <xs:simpleContent>
           <xs:extension base='xs:string'>
             <xs:attribute name='mechanism'
                           type='xs:NMTOKEN'
                           use='required'/>
           </xs:extension>
         </xs:simpleContent>
       </xs:complexType>
     </xs:element>

     <xs:element name='challenge' type='xs:string'/>

     <xs:element name='response' type='xs:string'/>

     <xs:element name='success' type='xs:string'/>

     <xs:element name='failure'>
       <xs:complexType>
         <xs:sequence>
           <xs:choice minOccurs='0'>
             <xs:element name='aborted' type='empty'/>
             <xs:element name='account-disabled' type='empty'/>
             <xs:element name='credentials-expired' type='empty'/>
             <xs:element name='encryption-required' type='empty'/>
             <xs:element name='incorrect-encoding' type='empty'/>
             <xs:element name='invalid-authzid' type='empty'/>
             <xs:element name='invalid-mechanism' type='empty'/>
             <xs:element name='malformed-request' type='empty'/>
             <xs:element name='mechanism-too-weak' type='empty'/>
             <xs:element name='not-authorized' type='empty'/>
             <xs:element name='temporary-auth-failure' type='empty'/>
             <xs:element name='transition-needed' type='empty'/>
           </xs:choice>
           <xs:element ref='text' minOccurs='0' maxOccurs='1'/>
         </xs:sequence>
       </xs:complexType>
     </xs:element>

     <xs:element name='text'>
       <xs:complexType>
         <xs:simpleContent>
           <xs:extension base='xs:string'>
             <xs:attribute ref='xml:lang' use='optional'/>
           </xs:extension>
         </xs:simpleContent>
       </xs:complexType>
     </xs:element>

     <xs:simpleType name='empty'>
       <xs:restriction base='xs:string'>
         <xs:enumeration value=''/>
       </xs:restriction>
     </xs:simpleType>

   </xs:schema>

